Component package for high power ASIC thermal management
A cooling plate for cooling microchip having redundant cooling fluid circulation. A primary fluid cooling loop removes heat directly from the microchip. A secondary cooling loop acts as a condenser for two phase cells, thus removing heat indirectly from the microchip. The cold plate may be fabricated as two parts bottom plate and top plate, wherein the primary cooling loop is formed in the bottom plate and the secondary cooling loop is formed in the top plate. Two-phase, self-contained cells may be immersed in the primary cooling loop and act to transport heat from the microchip to the secondary cooling loop.
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Embodiments of the present invention relate generally to enhanced and reliable cooling of advanced microchips, such as ASIC and other microchips used e.g., in servers within data centers.
BACKGROUNDCooling is a prominent factor in a computer system and data center design. The number of high performance electronic components, such as high performance processors packaged inside servers, has steadily increased, thereby increasing the amount of heat generated and dissipated during the ordinary operations of the servers. The proper operation of these processors is highly dependent on reliable removal of the heat they generate. Thus, proper cooling of the processors can provide high overall system reliability.
Electronics cooling is very important for computing hardware and other electronic devices, such as CPU servers, GPU servers, storage servers, networking equipment, edge and mobile system, on-vehicle computing box and so on. All these devices and computers are used for critical businesses and are the fundamentals of a company's daily business operations. The design of the hardware component and electronics packaging needs to improve to continuously support the performance requirements. Cooling of these electronic devices becomes more and more challenging to ensure that they function properly by constantly providing properly designed and reliable thermal environments.
Many advanced chips, and especially high power density chips, require liquid cooling. These chips are exceedingly expensive, so that every effort need to be taken to ensure proper heat removal from these chips. Moreover, the liquid cooling equipment must be highly reliable, since any irregularity in heat removal may lead to loss of the chips, causing loss of available computing power during the replacement operation, and even potential impact on the service level agreement which was handled by the lost chips. Importantly, existing solutions for electronics cooling and thermal management for processor do not provide redundancy on the module level, which means that they are a single failure point in the system. Specifically, failure to properly circulate cooling fluid within the cooling plate can lead to a failure of the corresponding processor. Therefore, enhanced reliability may be achieved by developing full end to end redundant cooling solutions for the chips, such that a single failure can be backed up by the designed in redundancy.
While liquid cooling solution must provide the required thermal performance and reliability, since data centers may have thousands of chips requiring liquid cooling, the cost of the liquid cooling system must remain acceptable. The cost of liquid cooling systems may include the cost of introducing redundancy to enhance reliability. Additionally, since different chips have different cooling requirements, it would be desirable to provide a cooling design that is adaptable and expandable to fit different server architectures and be compatible with different chip packaging.
Embodiments of the invention are illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements.
Various embodiments and aspects of the inventions will be described with reference to details discussed below, and the accompanying drawings will illustrate the various embodiments. The following description and drawings are illustrative of the invention and are not to be construed as limiting the invention. Numerous specific details are described to provide a thorough understanding of various embodiments of the present invention. However, in certain instances, well-known or conventional details are not described in order to provide a concise discussion of embodiments of the present inventions.
Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in conjunction with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification do not necessarily all refer to the same embodiment.
Incidentally, in the following embodiments similar elements are identified with similar reference numbers in the formal x ##, wherein the first digit x is replaced by the same digit as the figure number, while the next two digits ## are maintained consistent among the embodiments. Consequently, explanation of previously disclosed elements may not be repeated in subsequent embodiments.
Disclosed embodiments provide cooling plate for electronic devices, which utilizes multiple circulation loops to enhance the reliability of the cooling system. The cooling plate may be implemented for cooling various electronic devices, such as single-chip module (SCM), system on a chip (SoC), multi-chip module (MCM), System in package (SIP), etc. For brevity, these are referred to herein as microchips or simply chips, but any such reference should be understood to include any of these and similar variances of dies and packaging.
In various disclosed embodiments, the cooling plate includes multiple fluid ports that are couple to separate cooling loops. Additionally, the embodiments may incorporate multiple phase cooling cells in parallel with the cooling loops. Such embodiments enhance the cooling capacity of the cooling plate and enhances the reliability of the cooling system. In embodiments where two-phase cooling cells are used, one fluid cooling loop may be used to extract heat directly from the chip, while another fluid cooling loop may be used to extract heat from vapor in the cells as it condenses back to liquid, thus extracting heat indirectly from the chip. The structure and functions of these and other features would be described below in more details.
The bottom plate 205 includes one or more fluid channels 212 through which cooling fluid from a cooling system circulate. Immersed among the fluid channels 212 are a plurality of two-phase cooling cells 214. In one embodiment the channels 212 may be simply defined or formed by the placement and orientation of the cells 214, as will be further shown below. The two-phase cooling cells 214 are self-contained and are sealed, such that no fluid flows into or out of the cells 214. Rather, the fluid at the bottom of each cell get heated up by the chip 201 and evaporation occurs. The vapor rises to the top surface of the bottom plate 205 where it condenses and then flow back down. In this example, this process is enhanced by the provision of wicking material or structure 216 inside the cells 214. Thus, the bottom plate removes heat from the chip 201 partially by the fluid circulating within the fluid channels 212 and partly by the evaporation action inside the two-phase cells 214.
In this embodiment, the bottom plate 205 transfers some of the heat removed from chip 201 to top plate 215. The top plate of this embodiment comprises cooling channels 213 that receive circulating cooling fluid, separately from the fluid circulation of the bottom plate 205. Here, the fluid channels 213 of the top plate 215 incorporate fins 217 for enhanced heat removal. As cooling fluid circulates within the top plate 215, it keeps the top plate cold by extracting heat through the bottom of the top plate, thus enhancing the condensation action in the two-phase cells 214 of the bottom plate 205. By this action, the heat removed from the chip 201 by the cells 214 is at least partially delivered to the top plate, such that the fluid in cooling channels 213 indirectly remove heat from the chip.
As shown in
The redundancy of the two cooling fluid loops may be implemented in various ways. For example, different type of cooling fluids may be supplied to the bottom plate and the top plate. The different fluids may be circulated in two separate cooling systems employing independent pumps and conduits. Conversely, the type of fluid may be the same, but may be handled by two separate cooling circulation systems, i.e., flowing in different and separate loops. In this manner, if one cooling fluid circulation system fails (e.g., a pump failure or pump needs to be shut down due to a leak), the circulation would still function in the other system/loop to provide cooling to the microchip.
Thus, an arrangement of a microchip and a cooling plate is provided, wherein the heat generated by the microchip is partially removed directly from the microchip by a first or primary cooling fluid loop, and heat generated by the microchip is also partially removed indirectly from the microchip by a second cooling fluid loop which circulates cooling fluid independently of the primary cooling loop. The second cooling fluid loop indirectly removes heat from the microchip by enhancing condensation in two-phase cells that are immersed in the primary cooling loop.
Also, two-phase cells 314 are attached, e.g., welded, to the bottom surface of the top plate 315, thereby ensuring highly thermally conductive interface between the cells 314 and the top plate 315. Further, fluid channels 312 are formed in the top plate 315, in alignment with the fins 307 formed in the bottom plate. Thus, upon assembling the bottom and top plates, the fins 307 are positioned inside the fluid channels 312. The two-phase cells 314 are formed in alignment so as to be immersed in the primary cooling fluid and be positioned among the fins 307 upon assembly of the bottom and top plates. The shape, positioning and orientation of the two-phase cells 314 can be used to define the fluid channels 312. That is, the fluid flowing in the bottom plate would follow the paths defined by the fins 307 and the cells 314, thus the fins 307 and the cells 314 together define the channels 312. Each of the cells 314 may incorporate wicking structure 316. Once the bottom and top plates are assembled together, they may be attached to chip 301.
Thus, a method for fabricating a cooling plate for microchip is provided, comprising: providing a first metal plate and forming primary cooling channel in the first metal plate to thereby fabricate a bottom plate; providing a second metal plate and forming secondary cooling channel to thereby fabricate a top plate; fabricating a first set of inlet and outlet ports in the top plate, the first set having fluid passage to the secondary cooling channel; fabricating a second set of inlet and outlet ports in the top plate, the second set having an opening at bottom surface of the top plate to form fluid passage to the primary cooling channel upon attachment of the top plate to the bottom plate; and, attaching the top plate to the bottom plate.
Thus, according to disclosed embodiments, a cooling plate for cooling microchips is provided, comprising: a bottom plate incorporating a primary fluid cooling arrangement; a top plate attached to the bottom plate and having a secondary fluid cooling arrangement fluidly separated from the primary fluid cooling arrangement, wherein the secondary fluid cooling arrangement comprises fluid cooling channels formed in the top plate, a fluid inlet port fluidly coupled to the fluid channels and a fluid outlet port fluidly coupled to the fluid channels.
The two-phase cells 614 may be distributed within the flow area 612, such that some heat may be transferred from the cells 614 to the fluid in area 612. However, much of the heat from the cells 614 is intended to be transferred to the fluid flowing in channels indicated by 613. The fluid is delivered to channel 613 via inlet port 618 and is returned to the loop via outlet port 619, thus transporting the heat from the cells 614 out through outlet port 619. This enhances the condensation action of the fluid within the self-contained two-phase cells 614. This heat transfer and transport can be further understood by reference to
Thus, by the disclosed embodiments, a cooling device incorporating two independent cooling channels is provided. The cooling device comprises a bottom plate having primary fluid channels for directly removing heat from the microchip. A top plate is attached to the bottom plate and includes a secondary cooling channels for indirectly removing heat from the microchip and for providing redundant cooling loop. Therefore, two sets on fluid inlet and outlet ports are provided, one set for circulating cooling fluid in the primary channel and one set for circulating fluid in the secondary channel. A plurality of two-phase cells are provided in the bottom plate that, by evaporation and condensation action of the fluid contained therein transfer heat from the microchip to the fluid circulating in the secondary fluid channels. The cooling device is attached to a microchip or incorporated in microchip packaging.
According to further disclosed aspects, method for fabricating a cooling plate for microchip is provided, comprising: providing a first metal plate and forming primary cooling channel in the first metal plate to thereby fabricate a bottom plate; providing a second metal plate and forming secondary cooling channel to thereby fabricate a top plate; fabricating a first set of inlet and outlet ports in the top plate, the first set having fluid passage to the secondary cooling channel; fabricating a second set of inlet and outlet ports in the top plate, the second set having an opening at bottom surface of the top plate to form fluid passage to the primary cooling channel upon attachment of the top plate to the bottom plate; and, attaching the top plate to the bottom plate.
In the foregoing specification, embodiments of the invention have been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.
Claims
1. A cooling plate for cooling microchips, comprising:
- a bottom plate incorporating a primary fluid cooling arrangement, the primary cooling arrangement comprising a first two-phase cooling cell, a second two-phase cooling cell, and a primary fluid cooling channel positioned between the first two-phase cooling cell and the second two-phase cooling cell;
- a top plate attached to the bottom plate and having a secondary fluid cooling arrangement fluidly separated from the primary fluid cooling arrangement, wherein the secondary fluid cooling arrangement comprises fluid cooling channels formed in the top plate, a fluid inlet port fluidly coupled to the fluid channels and a fluid outlet port fluidly coupled to the fluid channels.
2. The cooling plate of claim 1, wherein the primary fluid cooling arrangement comprises a plurality of two-phase cooling cells including the first two-phase cooling cell, the second two-phase cooling cell, and at least one additional two-phase cooling cell.
3. The cooling plate of claim 2, wherein the primary fluid cooling arrangement further comprises:
- a plurality of primary fluid cooling channels including the primary fluid cooling channel and at least one additional primary cooling channel, the plurality of primary fluid cooling channels formed in the bottom plate;
- a primary fluid inlet port fluidly coupled to the primary fluid channels; and
- a primary fluid outlet port fluidly coupled to the primary fluid channels.
4. The cooling plate of claim 3, wherein the plurality of two-phase cells are immersed within the primary fluid cooling channels.
5. The cooling plate of claim 4, wherein the plurality of primary fluid channels comprise cooling fins.
6. The cooling plate of claim 4, wherein the plurality of two-phase cooling cells comprise wicking structure.
7. The cooling plate of claim 2, wherein the secondary cooling channels comprise fins.
8. The cooling plate of claim 1, further comprising a sealing ring provided between the top plate and the bottom plate.
9. The cooling plate of claim 1, further comprising a leak sensor.
10. The cooling plate of claim 5, wherein the cooling fins and the plurality of two-phase cooling cells are arranged in alternating positions.
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Type: Grant
Filed: Jun 8, 2021
Date of Patent: Aug 6, 2024
Patent Publication Number: 20220392826
Assignee: BAIDU USA LLC (Sunnyvale, CA)
Inventor: Tianyi Gao (Sunnyvale, CA)
Primary Examiner: Jacob R Crum
Application Number: 17/341,496
International Classification: H01L 23/427 (20060101); H01L 21/48 (20060101); H05K 7/20 (20060101);